Black azo dye.



NTTED STATES PATENT OF ICE.

MYRTIL KAHN, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBENFABRIKEN OF ELBERFELD 00., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

BLACK AZO DYEr.

ETPECIFICATION forming part of Letters Patent No. 726,695, dated April 28, 1903. Application filed January 27, 1903. Serial No. 140,719. (No specimens.)

mula:

(X meaning a halogen atom or a sulfonic group,) such as ortho-amidophenol-paraehloro-orthosulfonic acid, ortho-amido-phenol-ortho-para-disulfonic acid, or the like, with 1:5-dioxynaphthalene, having the formula m l I are entered into boiling water and allowed to remain there until the water is cold. The goods thus assume a high degree of gloss and softness, and, according to the effect desired, the potting may be repeated several times.

In carrying out my process practicallyI can proceed as follows, the parts being by weight: 22.5 parts of o-amidophenol-paraare diazotized in the usual manner, and the resulting diazo compound is stirred into a mixture of sixteen parts of l: 5-dioxynaphthalne with ice-water. Caustic-soda lye is added until the mixture is alkaline. The dioxynaphthalene enters into solution and the formation of the dyestuff begins. stirred for some hours the excess of causticsoda 'lye is neutralized by means of hydro- 'ehloric acid, and thenew dyestuff is precipitated by the addition of common salt, filtered OE, and dried. v

The new coloring-matter thus. obtained is in the shape of the sodium salt, a brownishblack powder soluble in water with a violet color and soluble in concentrated sulfuric acid of 66 Baum with a bluish-black color, turning greenish-black by the addition of a small quantity of ice and turning reddishviolet by adding a larger quantity of ice, a brownish-violet precipitate being obtained. It dyes wool from acid-bath violet shades. By subsequently treating the dyed fiber with chromium compounds reacting as oxidizing agentssuch as chromates, bichromates, or the like'the shades are changed to deep black, distinguished for great fastness to the potting process. They also resist milling and washing and possess a good fastness against the action of light.

Having now described my invention, what I claim is- 1. The herein-described new azo dyestufis derived from ortho-amidophenol derivatives having the above-given general formula and 1:5-dioxynaphthalene, which, when in a dry state, are brownish-black powders soluble in water with a violet color turning blue by add- After being I lene, which in the shape of the sodium salt,

is, when dry and pulverized, a brownishblack powder soluble in water with a violet color and being soluble in concentrated sulfuric acid of 66 Baum with a bluish-black color turning greenish-black by adding a small quantity of ice and turning reddishviolet by the addition of a larger quantity of ice, a brownish-violet precipitate-being thus obtained; dyeing wool from acid-bath violet shades which are changed to deep black by a subsequent treatment with chromium compounds reacting as oxidizing agents, substantially as hereinbefore-described.

In testimony whereof I have signed my name in the presence of two subscribing witnesses.

MYRTIL KAI-IN.

Vitnesses:

OTTO KoNIe, J A. RITTERSHAUS. 

